Comparison of Two Liquid Fly-Back Booster Configurations Based on Wind Tunnel Measurements

Kurzfassung

Within the German future launcher technology research program ASTRA a reusable concept called a winged liquid fly-back booster (LFBB) is under investigation. This booster should replace the solid rocked booster af Ariane 5. During the last design cycle the configuration LFBB Y7 was tested intensively in DLR trisonic wind tunnel TMK and hypersonic wind tunnel H2K at longitudinal and lateral flow conditions covering the complete flight trajectory from separation at hypersonic speeds down to the subsonic fly-back cruise regime. Six component force measurements were carried out with a 1:151 scale model to create a complete aerodynamic data set for stability, trim and control efficiency. In addition the characteristics of the flow field of this vehicle including the strong interaction between the canards and the wing was investigated in more detail. Therefore flow was visualised by oil flow pattern and schlieren pictures. Analysis of these test results together with numerical investigations lead to an improved design LFBB Y8. The main differences to the previous configuration are smaller canards with an unsymmetrical airfoil and modified leading and trailing edge sweep. The wing airfoil was replaced by an supercritical one. Another 1:151 scale model of this new fly back booster configuration Y8 is ready for wind tunnel tests. LFBB Y8 has a higher degree of details compared with LFBB Y7. Possible left and right canard deflections are -10°, 0° and +10°, body flap deflection are 0°, 5° and 30°. For comparison it is possible to omit the canards and the inlets of the three turbo engines. The presentation will summarise the results of the investigations of LFBB Y7 firstly. Secondly some characteristics of the flow field will be discussed. The presentation is focussed on a comparison of the two configurations.